1. The problem statement, all variables and given/known data Which of the following chemical compounds are acidic aqueous solutions? C2H2, C3H8, CH3OH, HCOOH, CH3OCH and benzene. 2. Relevant equations Not known. 3. The attempt at a solution The hydrocarbons aren't polar, that much I know. In the list there are, however, two polar compounds... I know the answer is that only HCOOH is an acidic aqueous solution, but no explanation is given. Am I supposed to be able to tell which ones are acidic aquenous solutions simply by looking at the chemical formula? Should I write the reaction first ([compound] + H2O → ...) and if so, how would I know what the products are in each case? After all, wouldn't I need the products in order to determine how much H3O- and HO-ions are produced?